Smelling female fruit flies but not mating with them can actually shorten males’ lives.

Drosophila melanogaster males not allowed to mate despite receiving tantalizing chemical sex messages lose about 35 to 40 percent of their normal life span, says molecular geneticist Scott Pletcher of the University of Michigan in Ann Arbor. Males’ fat stores also dwindle, and the flies prove less able to cope with starvation, Pletcher and his colleagues report November 28 in Science.